Channel-type induction furnaces are used for the melting and melt heat-retaining of metals, such as aluminum and aluminum alloys, an example, being shown by the Fredrikson et al Pat. No. 3,618,917.
Each furnace vessel requires its own channel-type inductor, used for both melting and heat retaining when output of melt is interrupted. The inductor is conventionally positioned in the furnace bottom in the hottest environment around the furnace, and during such periods it must be continuously force-cooled, its channel containing a continuous flow of melt at such times.